Mayor Michael Bloomberg has pledged that his proposed congestion pricing plan will decrease traffic by at least six percent in New York City. The federal government has pledged to kick in $354 million to get the program off the ground, if the city council and the state legislature approve the plan by March. A commission has been formed to figure out how best to implement the plan which, as proposed, would charge motorists between $8 and $21 per day to travel into Manhattan below 86th Street. But as officials work out the details here's a look at how congestion pricing has worked in London, the first major city to use the plan. Congestion pricing was introduced in London in February 2003. By most accounts, the program has been a success. Studies claim a reduction of 20,000 vehicles per day traveling into the city -- roughly a 10-percent decrease in automobile traffic -- and an increase in the average speed of traffic moving around the city. Peak-period congestion delays have declined about 30 percent. Bus ridership increased 14 percent, while subway ridership increased about 1 percent. A majority of businesses in London claim the plan has had no effect on business. Studies found that delivery times, in some cases, have been cut in half. Pedestrians and cyclists have claimed a positive response to the program. Congestion pricing has produced significant revenues. But here's what you don't know about congestion pricing in London: * The initial fee of 5 British pounds -- about $10 -- to enter the city between 7 a.m. and 6:30 p.m. was increased to 8 British pounds -- almost $16 -- in July 2005, a significant increase that was needed to offset costs; * About half of the revenue generated by the plan -- about $125.5 million of the estimated $259 million revenue for 2004-2005, the year the study was based on -- went toward operating the program, leading some critics to argue it is not as cost-effective as first claimed; * Outlying neighborhoods have claimed significant increases in traffic, with as much as a 10 percent increase in vehicle volume on peripheral roads; * A high rate of so-called "false positives," motorists being wrongly ticketed for treks into the city they did not make, were recorded during the first months of operation, as devices used to read license plate numbers misinterpreted characters or registration data. The false positive rates have decreased as the system has been perfected, but still are cause for concern transportation studies found; * Some smaller businesses claim they have been negatively impacted by the restrictions, first and foremost among them "bulk good retailers" who rely on customers who drive private cars. A significant portion of annual revenues generated by congestion pricing in London come from penalties, according to officials. About $30 million is generated by penalties, based on a system that charges drivers roughly a $160 fine if they fail to pay the toll fee. That fine is reduced to roughly $80 if it is paid within two weeks, but is increased to approximately $240 if it is not paid within one month. The system requires drivers to pay their toll within 24 hours of making their trip into London. Motorists can pay on-line or by cellphone or at specially designated "payment" machines. Weekly, monthly and annual toll passes are available at a discount. Motorcyclists and residents who live within the restricted zones are eligible for discounts of up to 90 percent, as are handicapped and disabled drivers. It remains unclear what impact -- positive or negative -- congestion pricing will have on New Yorkers. It does figure, though, to have the greatest impact on suburban drivers -- particularly Long Islanders and residents of Westchester -- who travel into midtown Manhattan, especially since their access to mass transit into the city may be limited. Other cities around the world are working on their own congestion pricing plans, among them: Trondheim, Oslo and Bergen in Norway; Singapore; Edinburgh, Scotland; and, Cardiff, Wales. Stockholm, Barcelona and Milan have all shown interest in establishing congestion pricing plans, as has Sao Paulo, Brazil. But there is very limited information available about those proposed plans at this time.